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jy_w_
Beginner
77 Views

Analyze openmp program - no openmp region displayed

Hi, I'm alayzing my openmp program using Intel vtune 2016. I used the -fopenmp flag when compiling and it runs on a 4-core machine. However, I can see no openmp region displayed in the summary pane in vtune, and there's no data when I refer to the openmp region in the bottom-up pane:

The analysis type is:

How can I get the analyzing results of openmp? Can anybody give me an idea of what I did wrong? Thanks!

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5 Replies
jy_w_
Beginner
77 Views

After some investigations, I found that the problem seems to be that my GCC OpenMP library (libgomp.so) contains symbol information. I'm using g++-5 on Ubuntu 12.04. Anybody knows how to make the library contain symbol information? I am really new to Linux, I know that in Fedora you can do something like "yum install gcc-debuginfo.x86_64", is there an equivalent command for Ubuntu? Thanks!

Dmitry_P_Intel1
Employee
77 Views

Hello,

VTune shows parallel region information based on instrumentation that is provided by OpenMP library from Intel compiler. For GNU OpenMP the analysis will be limited - VTune will be able to classify some of CPU time spent inside the library as spinning on barriers or locks or overhead on region creation.

If you need to stick with GNU compiler you can pre-load Intel OpenMP library (since they are compatible) and in this case you will be able to see OpenMP region mark-up.

Thanks & Regards, Dmitry

 

jy_w_
Beginner
77 Views

Thanks, Dmitry. For some other reasons, I need to use gcc for now. Do you know how to load the Intel OpenMP library? Many thanks!

Dmitry_P_Intel1
Employee
77 Views

You can build it from open source: https://www.openmprtl.org/

Please note that there will be some limitations in terms of analysis with GNU-compiled code and preloaded intel OpenMP - OpenMP region names will not contain function name and source line to recognize them. But with grid grouping /OpenMP Region/Function.. you will be able to expand a region and see the region pseudo-function and understand the context.

Thanks & Regards, Dmitry

 

jy_w_
Beginner
77 Views

Thanks for the link. Now I've successfully installed the Intel OpenMP runtime library, but I still cannot see the OpenMP region in my analysis result. Why is that? Could it be that the runtime library doesn't support g++-5?